Circuit breaker



OGLn 14, 1941. l J `M ANDERSON v v2,259,097

CIRCUIT BREAKER A Invent r: James M. Anderson,

i s At t orng.

0dv14, 1941 J. M. ANDERSON 2,259,097

CIRCUIT BREAKER y Filed Jan. 5, 1940 2 Sheets-Shea?l 2 'Figa lrwenbor James M/underusmmI @d www@ -H|`s Attorneg.,

Patented Oct. 14, 1941 n AUNITED STATES PATENT ori-ICE CIRCUIT BBEAKER James M. Anderson, Broomall, Pa., assigner to* General Electric Company, a corporation of New `York Application January 5, 1940, SerialrNo. 312,530 v (Cl. 20o-116) 19 Claims.

My invention relates to circuit breakers, more particularly to manually operated overload responsive circuit breakers, and has for its object a simple and reliable circuit breaker provided with means for resetting the thermal overload responsive means.

Another object of my invention is the provision of an auxiliary signal means which is operated to give a signal in the event`of an overload insuiilcient to open the circuit breaker.

This .combination is especially useful in distri# circuit position, the movable contacts I3 and II cooperating with suitable stationary contacts are secured to an insulating bar I2 which, in turn,

is secured to an arm I3 having 'a :stationary pivot I4. This arm I3 is provided with upstanding projections l5 to which are secured a pair of toggle links I6. These toggle links IB are, in turn, secured at rtheir other ends to a second pair of toggle links I1 which have their other ends normally fixed and secured pivotally to a bell crank lever i8 constituting a. trip or release arm. A stationary pivot I3 is provided for the bell crank lever and its other end-23 extends upward and is normally secured by a rotatable the opening of the circuit breaker on overload whereupon the toggle is broken and the xed end of the toggle returns to a position to be again secured by the current responsive means.

I also provide an auxiliary switch for controlling a signal circuit, which auxiliary switch is actuated by the operating member of the main circuit breaker contacts and is moved to a position to be held by the vcurrent responsive means when the main contacts are moved to their closed positions. This arrangement provides for movement of the auxiliary switch member to its latched position without opening the main circuit breaker in the event that the auxiliary switch is released by the current responsive means to operate the signal while the main contacts remain in their closed positions.

For a more complete understanding of my invention, reference should be had to thev accompanying drawings, Fig. l of which is a side elevation view of a circuit breaker embodying my invention; Fig. 2 is a plan view of the device shown in Fig. 1; Fig. 3 is a view inperspective of the operatingmechanism with certain parts enlarged for purposes of clarity; Figs. 4 and 5 are simpliiied views showing the4 operating mechanism respectively in the manual open and automatic. open before automatic reset positions; while Fig. Sis a fragmentary view showing the manually operated latch in theA open circuit position.

Referring to the drawings, particularly Fig. 3

which showsthe circuit breaker in itsv closed trip shaft 2| vhaving a slot 22 for passage of the upper end of the arm 20. This trip shaft, slot and release arm arrangementjs substantially as described and claimed in U. S. Patent No. 2,067,797, issued on January l2, 1937, to RobertvW. Smith.

With the circuit breaker in its closed circuit position, as shown in Figs. 1, 2 and 3, a relatively strong helical spring 23 applies a force tending to break the toggle links I 6 and i1 upward and 'with4 respect to the arms 3|, 32.

open-the circuit breaker.V It is prevented from doing this, however, by a. latch member 24.

More specifically, the spring 23 surrounds a stationary pivot pin25 and has one end held against a vstationary stop 26. Its other end engages a cross bar 21 between two parallel links 28 and 29 which have their ,lower ends pivoted on the .pivot 25. This bar 21 lies in a notch 30 in an arm 3l which is pivoted on the pivot 25 and forms with a. complementary arm 32 an operyating arm, Ithe movable end of which is conas indicated in dotted lines in Fig. 1. The notchI 30 is large enough to give the pin 21 considerable freedomvof movement about its pivot 2l The pin 21, however, is forced by the spring 23 in a clockwise direction about its pivot ,as seen in the drawings against the right hand wall of the notch 33 whereby the spring exerts a force on the arm 3l tending to move it in a'clockwise direction (Fig. 3) about the pivot 23.

Movement ofthe arms 3|, 32 is prevented, however, by the latch 24 which has a projection 35 hooked over a pin 34 extending between the direction to hold the latch 24 in latching position on the pin 3B.

For manual opening of the circuit breaker, two arms 39 are depressed about the pivot- 25 by an actuating plunger 30, i. e., moved in a clockwise direction, as seen in Fig. 3. This brings a cross connecting strap or bar il between the two arms 3Q adjacent the pivot 25 into engagement with a projection l2 on the trip arm 2,63. Further depression of the arms 39, therefore, carries the tripl arm 25 in a clockwise :tion about its pivot Si until the pin 3S is released. Thereupon the spring 23 throws the arms El, 32 upward breaking the toggle links it, il in an upward direction. This moves the switch arm i3 in a counterclockwise direction about its pivot it to its open position, the switch arm being biased -to this position by the springs 62a. An extension 12b on the arm it engages the supporting structure to limit the opening movement of the arm E3. This open position of the mechanism is shown in Fig. d.

This opening action is, furthermore, edected withA a snap action by means of the springs 253,

i205 and a spring d3' connecting a pin d! joining the outer endso the arms 3@ with a pin i5 connecting the'upper ends of the arms 2d, 2d. Thus, as the armste are depressed, the spring i3 is stretched and when the latch Zd is moved toits released position, the springs snap the arms 28 and 29 and the parts connected thereto including the movable contacts liti, il to openV 48 and 4l are connected respectively in circuit with these contacts. -These devices preferably,

as shown, are bimetallic thermostatic elements.

They are each in the form. of a hair pin with the openends of the hair pin xed each to a suitable support and with their looped ends 46 is secured to the base 48 at a point nearthe contact i@ so asto facilitate the connection of the movable arm of the contact through a :flexible -conductor i9 to one end of the thermostat. Also the .thermostat di ds similarly arrangedwith respect to the contact il. The thermostat from its point of supportextends laterally with respect toi the base andalso toward the lefthand end, seen in Figs. l and 2, at an angle with the base. l

By means of this inclined arrangement of the thermostats, theirmovable ends are brought into position to engage projections 5@ and 5i on the `trip shaft 2i so as to turn the shaft clockwise in response to a predetermined current through the thermostats and thereby release the trip arm 2d. When this occurs, -the trip arm 2d moves in a clockwise direction, as seen in Fig. 3. The current responsive means is thus constituted by one or both of the thermostatsand, in addition, the rotatable trip shaft 2l and the parts y they do not remain in these positions. Thereupon d@ is raised move together in a predetermined f relation' with respect to each other about the pivot 25. The pin 2l now engages'the opposite side of the slot-30, i. e., the left hand side as 'seen in Fig. 3, and moves the arms 3l, 32 downward whereby link 33 forces links i5, il downward to close the switch and to store energy in springs da, and puts the arms di, 32 in a position such that the latch 35 again hooks over the pin 35, as shown in the drawing.

During this upward and downward movement of the arms 3i, 32, the pfin 36 (Fig. 6) rides on the curved edge 35a. of the projection 35 on the latch 24, whereby the projection 35 is prevented.

lowered so thatthe projection 35 is ready to move overthe pin 36 and latch it when the arms reach their lowermost closed circuit position.

'36 while the arms 3i,I 32 are being raised and Toeffect the automatic opening of the device inerespon'se to the current through the contacts t@ or il, two 'load responsive operating devices,`

the arms di, 32 move upward in accordance with their bias by the spring 23 and break the toggle arms i6, il upward thereby returning y the trip member 2@ back to its latched position,v shown in Fig. 4 of the drawings, where itisshafts 55 and t-made of. a suitable electrically insulating material such as a molded compound.

Through these hollow shafts extends a metal rod 5l with an enlarged central part 2i provided with the latching slot 22. The insulating parts' 55 and 56 carry projections 58 and 5ta to which is secured a metal arm 59. 0n the outer end of this arm isa button 60, preferably made of a molded compound, which is provided withta tapped bore cooperating with the threaded end` of a rod 5l; The lower end of this rod 5l pivotally engages the end of an arm 62` which is secured to the central metallic portionZl of thetrip shaft. A' wire spring 63applies aforce tending to separate-the Varms.59 and 62; which force is opposedby the connection. formed-by the rod Sl.- Also the arm 62 is normally heldtinfa-predeter-r having one end connected kto anida-frame lmember 65 and its other end connected to aprojectng arm 65 onthe'arm 62. Thisspring pulls upward biasing the arm 62 as seen-in Fig. 3, ina counterclockwise direction, and normally holding the end of the arm 66 against a stop`-61\.(Fig. 2) on the side plate 65.

Thus, when the button 60 is turned, the connecting rod 6| is lengthened or shortened as the case may be, and -thereby the arm 58 and the hollow insulating shafts 55 and 58 as a unit are adjusted about the shaft 51. I n'this way the electrically insulating trip -projections 50 and 5| are adjusted with respect to the ends of the thermostats so that the thermostats have a smaller or greater amount of movement required of them in 'order to engage the projections 50 and`5| and turn the trip shaft far enough to release the trip member 20. A further equalizing adjustment to compensate for variations in manufacture of the thermostats is provided byan adjustable insulated button 61a (Fig. 1) on the end oi each thermostat, which button moves to engage the projections 58 and 5|.

Also built into the circuit breaker is a bridging contact member 68 (Fig. 3) electrically separate from the circuit breaker described, which is normally held in open circuit position but which is released upon the occurrence of an overload current somewhat lower than that required to trip open the circuit breaker contacts I8 and 4The object of this is to give an indication as by the lighting of a lamp or the ringing of a bell that an overload, although not a dangerous overload, exists. On heavier overloads, the contact member 68 will give indication as described, just prior to opening of breaker contacts I8,

. while on short circuit 68 will indicate practically simultaneously with opening of the breaker contacts. If the circuit breaker is not opened, the signal indicates that the equipment has been subjected to some overload, while if the breaker be opened the signal indicates that there has been -a heavy overload or short circuit.

This bridging contact member 68 is mounted for movement on an arm 68a, in turn mounted on the pivot I9. On the-arm 68a is a projection 69 pivotally secured thereto on a pivot 10 and adjustable with relation thereto about the pivot by means of a. screw 1|. The upper end of this arm 69 normally engages a projection 12 carried by the arm 62 and, therefore, movable with .the trip shaft. A helical spring 13 applies a biasing force to the bridging contact arm in a clockwise circuit closing direction as seen in Fig. 3.

This spring 13 has one end 13a (Fig. 3) attached to the arm 68a, its other end 13b being suitably secured to a support for the parts (not shown in Fig. 3) in the manner of spring 38.

'I'his projection 12 and the arm 69 are so arranged relatively that upon a predetermined movement of the trip shaft caused by a predetermined current, adjustment for which may be made by the screw 1 I, the projection 12 moves clockwise as seen in Fig. 3, suiliciently to release the arm 69 whereupon the bridging contact is moved by the spring 13 to bridge the two stationary contacts 14 and thereby give a signal, such as4 lighting a lamp 15, or ringing a bell.

This ind-icates that an overload exists or has' will be mounted in the tank of an outdoor service transformer and immersed in the transformer oil with the contacts I and connected in theo Thus the lamp 15, visible from the exterior of 'the transsecondary circuit of the transformer.

former,` gives an indication of overload although circuit breaker; but also makes known the fact that there had been a heavy overload or short circuit on the line. y

The bridging contact 68 is opened when the member I6 is pulled upward to close the circuit breaker, the contact 68 being operated by means of an operating rod .16 which extends loosely throughan aperture in an extension 11`cf the pin 45. Also this rod 16 has an oiset 18 which, when the pin I5 is moved counterclockwise about its pivot'25, is engaged by the extension 11 and upon continued movement of the extension 11, the rod'16 returns the latch arm 69 to the latched position shown in the drawing, Fig. 3. In other words, the arm 69 may be and is pushed back under the projection 12, without tripping the circuit breaker, the bias of the spring 64 returning trip shaft 51 to full latching position after 6! is latched by 12. Obviously'the contact 68 is opened in the same manner after its closure in response to an overload insufficient to' open the main contacts I0 and Il. Thus it will be seen that this reopening or resetting of the auxiliary contact 68 has no effect on the main contacts I0 and when these contacts arealready closed, the main contacts simply remaining closed.

It is to provide for this resetting of the bridging signal contact 68 that the loose connection is provided between the arms 28, 29 and the arms 3|, 32, this connection being formed by thepin 21 which moves in the elongated notch 30. Preferably a similar slot is provided in the arm 32. Thus, after the switch 68 has been opened as'previously described the arms 28 and 29 are moved clockwise by the spring 23 when the closing handle or member is released, until the pin 21 engages the right-hand end of the notch, as viewed in Fig. 3. This moves theprojection 11 clockwise away from the shoulder 18` so that when the arm es is again released, it is' free te turn and bring the bridging contact 68 into its closed circuit position..

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not fwish to be limited thereto since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A circuit breaker comprising a switch member, an operating member connected to move said switch memberbetween its open and closed circuit positions, a spring for biasing said operating member to. cause movement of said switch member to said open circuit position, a. latch ating member, and current responsive means for causing movement of said switch member. to its open circuit position independently of said first operating member.

2. A circuit breaker comprishig a switch member, an operating member connected to move said vswitch member between its open and closed circuit position-s, a spring for biasing said operating member to cause movement of said switch member to said open circuit position, a latch for holding said operating member against the force applied by said spring, a second operating member mounted for movement in one direction to move said rst operating member to a position tqbe held by said latch and in another direction independently ,of said iirst operating member to move said latch to release said iirst operating member, and currentresponsive means for causing movement of said switch member to its open. circuit .position independently oi said iirst operating member, said switch member being rarranged to move said latch to a position torelease said iirst operating member when said switch moves to its open circuit position.

3. A circuit breaker comprising a switch member, spring -means biasing `said switch member to its open circuit position, a release memestaca? 45. A circuit breaker comprising a switch arm,

spring means biasing said switch arm toitslfcircuit positiorna release arm, a one and. connected to said switch arm and its other end connected to said release arm, thermal current responsive means normally holding said releasearm in a predetermined^ position against the bias of said switch arm to its open position, an operating arm connected to make and break said toggle so as to move said switch arm between, its open and closed circuit positions, a

toggle spring for biasing said operating arm to4v a position to break said toggle and move said switch arm to said open circuit position, a pivot'ed ber, current responsive means normally holding j said release member vin a predetermined position, a `toggle having one end connected to said switch member and its l,other end connected to be held normally by said release member, an operating member connected to make and break saidl toggle so as to move said switch member between its open and closed circuit positions, a

toggle spring for biasing said operating member to a position to break said toggle whereupon said switch member moves to said open circuit position, a latch for holding said operating member against the force applied by said toggle spring, and a second operating member mounted for movement in one direction to move said ,rst operating member to a position to be held by dit said latch and in another direction to move said l latch to release said first operating member.

d. A circuit breaker comprising a switch arm,

spring means biasing said switch arm lto itsy open circuit position,- a release arm, current responsive means normally holding said release arm in a predetermined position, a toggle having one end connected to said switch and its other end connected to beheld normally w said release arm, an operating member connected to make and break said toggle so. as to move said switch arm between its closed and open circuit positions, a toggle spring for biasing said latch for holding said operating against the force applied by said toggle spring, ual operating means for moving said latch to 'a position to release said operating arm Awhereby said switch arm is opened with a snap action, and means carried by said switch arm for moving said latch -to its released position when said switch arm is opened by said thermal current responsive means in response to a predetermined current whereupon saidv toggle spring moves said operating arm 'to break said toggle and thereby return said current responsive release arm to a position to be secured by said thermal means.

6. A circuit breaker comprising a` switch arm, spring means biasing said switch arm to its open circuit position, a release arm, a toggle having one end connected to said switch and its other end connected to said release arm, means normally holding said release arm in a 'predetermined position against the bias of said switch arm to its open position, thermal current responsive means for causing movement of said holding means to free said release arm, an operating arm connected to said toggle so as to makeand break said toggle and thereby move said switch arm between its open and closed circuit positions, a toggle spring lfor biasing said operating arm for movement to break said toggle and move said switch arm to said open circuit position,

against the force applied by said toggle spring,

l a second operating arm, means connecting said operating arms for movement together to make said toggle when said second arm is moved in one direction, a second spring connecting said operating arms so as to. be tensioned by movement of said second operating arm in the other direction, means carried' by said second operating arm for moving' said latch toits released position when said second arm is moved in said second direction whereby said switch arm is opened with a snapaction, and means carried by said switch arm for moving said latch to its released position when. said switch arm moves to its open circuit position so that when said switch arm is opened by said thermal current responsive means. said toggle spring moves said operating arm to break said toggle and thereby tion to be held vby saidlatch and in another direction to move said latch to release said iirst operating member, said switchv arm being arranged to move said latch to a position to release said first operating member when said switch arm mov'es to its open circuit position so that when said switch arm is opened by move,-

ment oi said` release arm in response toga pre determined current said toggle spring moves said operating arm to break said utoggle and th'ereby return 'said .release arm to said-predetermined position.

return vsaid current responsive release arm'to a position to be secured by said thermal means. 7. A. circult/ breaker comprising a switch member, a spring for biasing said switch member to an open circuit pition, an operating member connected to move said switch member between its open and closed circuit positions,

a second operating member, a lost motion connection between said operating members whereby said second operating member is movable to operate said rst operatingmember, a second .spring for biasing said second operating member toggle having spring v.tor

. 9,259,097 relativetosaidrstoperating memberinad'irecuoacopositetoitsareuirelosingaireeuonof movement, a currmt responsive means for causlngtoisaidswitchmembertoitsopen mt unc-aannam 'of mst operating member, a secondswitch member, a

manbenaspringforbiasingsaidsecondswitch member'toapredetermmedposltiontooperate device. latching means for. securing said second switch member-,in another position, an operating connection between said latching means and said current responsive means whereby said'latching means is moved to release'sald ,mondswitchmemberinresponsetoalower current than that required to cause movement erfeaia are: einen member te its epen dreun position, a connection between said second operating member and said second switch member formoving said second switch member to a.A Yposition-to be secured by said iatching meansl concurrentywith movement of saidiirst operating member to it's closed circuit position, said second spring thereafter moving said second member independently of saidriirst member to release said second switch member. I

a. s 'eiremt breaker eemmanga switch 'said Y operating member, said switch arm being'arranged to-move.said latch to a position torelease said ii'rst operating-,member when switch arm moves to its open circuit posia second contact arm, a signal device con- A by said second'contact arm, a second biasingsaid second contact arm'to current than that required to release said nrst switch amt-Va connection between; said secondV memberandtherebymovesaidsecondoperaung membertoapodtiontobeheldbyssidlatch and movable in another direction independently of said second operating member to movesaid latch to release said `rst operating member, current responsive means for causing movement ot'saidswitcharmtoiisopencircuitposition independently ot said' iirst operating member, said switch'arm being arranged to move said latchtoapositiontorelsesaidrstoperating memberwhensaidswitcharmmovestoitsopen circuit position, a second contact arm, a signal devicecontrolledbysaidsecond switch arm.a second spring for biasing-said second switch arm to apredetermined position, latching for securing said second switch arm in another position, an operating connection between'said latching means and said current responsive means whereby said lstching means is moved to releasesaidsecondswitchsrmintoavlower current than that required to move said iirstswitcharmtoitsopencircuitposition,v

pivotandbeingconnectedtogetberior limited angularmovementwithrespeettoeachother, an operating member engagingsaid auxiliary switch operating arm for t oi said arms togetberinonedirectionaboutssidpivottociose said main switch member and operate said 'auxiliaryswitchmember-toonepositiomlatching means holding said main switch operating arm in said closed circuit position., means biasing said auxiliaryv switch operatingearm in an opposite direction away from said auxiliary switch member to provide for'mvement of said auxiliary switch member independentiyot saidauxillary switch operating arm, and current responsivelatchingmeansiornormallyholdingsaidauxil- 'iaryswitchmemberinsaidonepositiom said second's'witch arm in response to a lower n QL-with movement 0 1 said iirst n member; to 'a posi-.ion te be held by said laten.

sdid iir'st spring thereafter moving said sec" operating member independently-oi said operating memberto release said second.4

" Agcircuit breaker comprising a switchrm', an operating member connected to move said arm Vbetweenits open and closed circuit positions, vs. second operating member, a lost motionconnection between said operating mem-y bers, .a spring for biasing said second operating member to move said switch arm to said open .circuit position. a latch for holding said first operating member against the force applied by said 4spring, a. third operating member movable in one direction to 'engage said secondoperating 75 'n.seneiutb'reaxereempnangemnnmfsn' member, an auxiliary switch member, an' operating arm for each ot'said switch memberavsaid arms being moimted for movement on a 'common pivot and being connected together. for

limited angular movement with respect to-each other, an operating member said auxiliary switch operatingarm for movement o! said arms together in one directionV about said pivot to close said main switch member and open said auxiliary switch member, latching means holding said main switch operating arm in said closed circuit position, means biasing said auxiliary switch operating arm man opposite direction away from said auxiliary switch member to provide for closing movement offsaid auxiliary .switch member independently ot said auxiliary switch operating arm, and current responsive laching means for normally holding said auxiliary switch member in an open circuit position, and` current responsive means for causing movement of said latching means to release said auxiliary switch member. Y

12. A circuit breaker comprising a main switch member, an auxiliary switch member, an operating arm for each of said switch members, said' arms being mounted for movement on a lcommon p ivot and being connected together for limited angular movement with respect to each other, an operating member engaging said auxiliary switch operating arm for movement of said arms 4together' in one direction about said pivot to close said main switch member and open said auxiliary switch member, l-atching means holding'said main switch operating arm in said closed circuit position, means biamng said auxiliary switch operating arm in an opposite directionv away from said auxiliary switch member Ito provide for closing movement'of said auxiliary' predetermined positions, currentresponsive means for normally securing said switch members in other positions against theirbiases. said current responsive means being arranged to release said auxiliary switch member in response to a lower current than required for the release of said main switch member, an operating member, and connections between said operating member and said switch members providing for moveswitch memberl independently of said auxiliary switch operating arm, and current responsive latching means for normally holding said auxiliary switch member in an open circuit position and said main switch member in a closed position, said latching mealns being arranged to release said auxiliary switch member in response to an increased current before said main switch member is released.v Y

13. A circuit breaker comprising a pair oi switch members, an operating member conneeted to move said switch members between open and'closed circuit positions, a trip member mounted Afor movement on a pivot axis, a latch member normally held by said .trip member to' hold said switch members in closed circuit positions but released for opening movement of said switch members when said trip member is turned on'its pivot axis, an aaustment membermounted for movement on said pivot axis, a pair of thermostats arranged to engagesaid adjustment member and connected respectively in circuit with said switch members, a member adjustably secured to each of said thermostats and engaging said adjustment member for movement of said adjustment member when said thermostats are heated by the'current therethrough, and an ad- ,instable` connection between said adjustment ment of said switch members -to saidpredetermined positions independently of said operating member and for movement of said operating member in a rst direction to move said main and auxiliary switch members to said other positions against their biases, said operating mem-' `ber being movable in a second direction to cause movement of said main switch member to said predetermined position independently of said auxiliary switch member.

16. A circuit breaker comprising a main switch I member, an auxiliary switch member, independently movable main and auxiliary latch members connected respectivelyto said main and. auxiliary switch members, means biasing said switch members independently to predetermined positions, current responsive means for normally securing said latch members in predetermined positions in which said switch members are held in other Y positions against their biases, said-current responsive means being arranged to release said Y auxiliary latch memberl for operation of said member and said trip member providing for independent adjustment of said adjustment member with respectuto'said trip member andfor movement of trip member with said insulatingl r'nember by said thermostats.

141 A- circuit breaker.. comprising a`pair of,

Y- switch` members, an operating member connected to move said switch members between open and auxiliary switch memberin accordance with its bias in response to a lower current than required -for the release of said main latch member-,gan

operating member, ,and\ connections between said operating member and said switch members providing for movement of said switch members to said predetermined positionsindependentlyzoi said operating member and for movement of said operating member in a ii'stv direction to move .said main and auxiliary switch members tsaid other positions against their biases and thereby to move said auxiliary latch member to a posi;-A tion to be held by said current responsive means,

said operating member being movable in a second direction to cause movement of said main swit'el member to said predetermined position independently of said auxiliary switch member.

closed circuit positions, a trip shaft provided with a. slot, a latch member'normally engaging and held by said shaft to hold said switch members in closed circuit positions but released for opening movement 'oi said switch members when said shaft is rotated to bring said slot into register with said insulating member by said thermostats.

15. A circuit breaker comprising a main switch member, an auxiliary 'switch member, means biasing said switch members independently -to 17. A circuit breaker comprising a main switch member, an auxiliary switch member, means 'biasing said main switch member to its open circuit position and biasing said auxiliary member to a irs't position, current responsive means for normally securing said switch members in their closed and-rst positions, respectively, against their biases, said current responsive means being arranged to release said auxiliary switch member in response to a lower current than required for the release of said main switch' member, an operating'member, a connection between saidv operating member andv said ,Y

switch member providing for opening movement of said main switch member independentlyf'of 7 said operating member and for movement of said operating member in a iirst direction to move said main switch member to its closedycircuit position, a lost motion connection between/said operating member and said 'auxiliary switch member providing for movement ot said auxiliary switch member `to a second positionto 'be held by said current responsive means upon movement of said operating membernin direction, a spring for moving said operating -membera' predetermined amount in a second direction to provide for movement 'of said alixlatch member to maintain said switch member in its closed circuit position, an operating member connected to said linkage means so as to move said switch member between its closed and open circuit positions, spring means `:Ior biasing said operating member to a position to move said switch member to its open circuit position and move said latch member to a position to be held by said current responsive means, a second latch member for holding said operating member against said spring means, said second latch member being arranged to be moved by said switch member to relea'se said operating member when said switch member moves to its open circuit position upon release of said latch member by said current responsive means, whereby said rst latch member is returned to a. position t0 be held by said ctn'rent responsive means.

19. A circuit breaker comprising a switch' member, spring means biasing said switch member to its open circuit position, a latch member,

current responsive means normally holding said latch member in a predetermined position, linkage means connecting said switch member to said latch member to maintain said switch member in its closed circuit position, an operating member connected to said linkage means so as to move said switch member between its closed and open circuit positions, spring means for biasing said operating member to a position to move said switch member to its open circuit position and move said latch member to a position to be held by said current responsive means, a second latch member for holding said operating member against said spring means, said second latch member being arranged to be moved by said switch member to release said operating member when saidc switch member moves to its open circuit position'upon release ot said first latch member by said current responsive means, whereby said first latch member is returned to a position to be held by said current responsive means, a second switch member biased to a predetermined position and normally held in a second position bysaid current responsive means and a second operating member having aolimited freedom of movement with respect to said nrst operating member and movable to move said auxiliary switch member to its predetermined position and concurrently therewith move said nrst operating member to close said main switch member.

JAMES M. ANDERSON. 

